Process of extracting ammonia from distillation-gases.



PATENTED NOV. l, '1904.

R. BRUNGK. PROCESS OP EXTRAGTING AMMONIA PROM DISIILLATION GASES.

APPLIOATION'PILED AUG. 6, 1903.

N0 MODEL.

/N VEN Tof? w/T/vcoc TTOPA/m UNITED STATESA Patented November l, 1904.

PATENT OFFICE.

RUDOLPH BRUNCK, OF DORTMUND, GERMANY, ASSIGNOR TO THE FIRM OF FRANZBRUNOK, OF DORTMUND, GERMANY.

PROCESS OF EXTRACT-ING AMMONIA FROIVIADISTILLATION-GASES.

SPECIFICATION fon-ning part of Letters Patent No. 773,784, datedNovember 1, 1904.

Application filed August 6, 1903. Serial No. 168,504. (No specimens.)

To all whom t may concern.

Beit known that I, RUDOLPH BRUNCK, doctor of philosophy, a subject ofthe King of Bavaria, (whose post-ofice address is No. le Prinz FriedrichCarl Strasse, Dortmund, Kingdom of Prussia, German Empire,) haveinvented a new and usefulProcess of Extracting Ammonia fromDistillation-Gases; and I do hereby declare that thefollowing is a full,clear, and exact description of my invention, which will enable othersskilled in the art to which it appertains to make and use the same.

This invention relates to the extraction of ammonia and its compoundsfrom the gases evolved during the dry distillation of coal, brown coal,wood, peat, and other substances, especially from the gases produced bythe carbonizationv of coal, either in gas-workslor in coke-ovens.

It is known that in order to extract the ammonia and its compounds fromthe distillation-gases the latter are either treated with dilute acidsor with water, which latter process is now in use on a large scale.IVith the first process large quantities of the absorbing-acid arerequired, and'to obtain therefrom the absorbed ammonia in the form ofsolid salts these large quantities of dilute acid have to beconcentrated, which not only causes a great cost for fuel, but alsonecessitates an expensive apparatus. Vith the other process thedisadvantages are by far greater. It requires large quantities of water,and the free ammonia has to be fixed by the addition of acids, and thedilute solution must be concentrated, or the liquor is, as most in use,mixed with lime and distilled to drive out the ammonia, which isabsorbed anew by means of water or acids.

It is the object of my invention to do away with those deficiencies andto obtain solid ammonia salts on a direct way-that is, from the hotgases themselves without previously removing the vapors of water and tarcontained in these gases.

To this end my improved process consists in conducting the hot gaseswithout being deprived of the vapors of water and tar in a fine state ofdivision through suitable concentrated acids-for instance, concentratedsulfuric acid-and maintaining the temperature of the absorbing-acid sothat no condensation of the water-vapors can take place, whereby theabsorbed ammonia is separated in the form of solid salts. The salt isbaled out in the ordi- 5 5 nary fashion or in any other way, and freshacid is supplied when needed. The acid must be kept at a temperature ofat least 800 to 850 centigrade, so as to prevent the steam contained inthe gases from condensing. The tempera- 6o ture may preferably bemaintained by the hot distillation-gases themselves and is regulated bypreviously cooling the gases as needed.

In other cases the acid may be heated by means of indirect steam,utilizing for this purpose, 65 for instance, the exhaust-steam of theengine.

In order to avoid stoppages in the path of the gases, the separationofthe solid salts is preferably effected in open vats only. After leavingthe-flatter the gases may also be treated, 7o' if necessary, in otherabsorbing apparatus of any known construction such as washers,scrubbers, or the likeein order to remove the last traces of ammonia. Inthis case only as much ammonia is to be absorbed by the acid as willcause no salt deposits and stoppages in the closed apparatus. This acidis then run into the openvats, in which the salts settle in the mannerabove described. The same treatment may be applied prior to con- 8Oducting the gases into the vats. When proceeding in this manner, thegases are also previously cooled as needed before entering the saidabsorbing apparatus.

The accompanying drawings illustrate one 8 5 form of carrying out thepresent invention.

Figure l is a longitudinal section through line 1 1, Fig. 3. Fig. 2 is atransverse section; and Fig. 3 is a plan, part of the pipes e and fbeing broken away.

The receiving-vat a is filled with concentrated acid-for instance,sulfuric acid-in which the vessel I) is immersed, the latter being openat the bottom andy divided into a number of compartments c c c2 c3 c4and Z d 95 Z2 Z3 di, the partition-sheets of which are serrated at theopen side of the vessel Across the top of these compartments there aretwo pipes e and f, the former communicating with the compartments c c c2c3 c and the latter' with the compartments l d Z2 d d". The gases areiirst conducted into the chambers c c' c2 c c4 through thedistributing-pipe e and then pass through the aeid below the serratedpartition-sheets, with the effect of being finely divided. They nowenter into the chambers CZ d Z2 d3 d* and are thence led off through thecollecting-pipe f. The ammonia salt settles on the bottom of thereceiving-vat and is baled out at intervals. If necessary, the salt isfreed from any tar particlesY by washing it with a saturated solution ofthe same ammonia salt. The small quantity of tar condensed on thesurface of the acid during the process flows off continuously through anaperture o in the vat ft.

If according' to the one method now in use the lgases are treated withdiluted acids, the solution must be strongly concentrated in order torecover the solid salt. In comparison with the other system of washingthe gases with water as almost universally adopted a still greateradvantage is secured by my improved process, because the ammonia isextracted directly in the shape of solid salts. In the other case verylarge quantities of Water are required for extracting the ammoniacompletely. If the ammonia is then fixed to the acid, the solution mustbe concentrated, so as to obtain the ammonia salts, or the ammonicalliquor has to be subjected to distillation with une.

A further important feature of the process is the fact that the nuisancehitherto caused by the exhausted liquor and foul lime is now done awaywith, so that the ammonia-works are no longer put to the heavy expensesfor the removal of these offensive matters. Moreover, the difiicultiesin obtaining permission for the working' of ammonia-factories are thusobviated.

In order to show the economical advantages of my invention, both asregards the cost of erecting plants and their simple and cheap working,the carbonization of coal with byproduct recovery tar and ammonia-may bequoted as a striking example. The capital amount invested in an ordinaryinstallation of sixty coke-ovens constructed on the new system will beabout /three thousand live hundred pounds sterling less than'at present.The working and maintenance of the plant will allow of still greatereconomy, as up to fifteen hundred and lifty pounds sterling are savedper annum, which is equivalent to nearly forty per cent. of the presentworking expenses. As to the manufacture of illuminating-gas a greatadvantage is attained by the highly-reduced number of coolers andwashers. Moreover, the treatment of ammonical liquor in stills isavoided, so that the steam required for this purpose is now saved.

Vhat I claim as my invention is* l. The process of extracting ammoniafrom gases produced in the dry-distillation process, which essentiallyconsists in conducting the hot gases without being deprived of thevapors of water and tar in a fine state of division through concentratedacids in open Vessels, regulating the temperature of the acid to atleast 80O to 850 centigrade, removing the tar from the surface of theacid, baling out the deposited solid salts, and supplying freshconcentrated' acid, substantially as and for the purpose stated.

2. The process of extracting ammonia from gases produced in thedry-distillation process, which essentially consists in conducting thehot gases without being deprived of the vapors of water and tar in afine state of division through concentrated acids in open vessels,regulating the temperature of the acid to at least 8OO to 850centigrade, removing the tar from the surface of the acid, baling outthe deposited solid salts, extracting the last traces of ammonia fromthe outgoing gases by special treatment with concentrated acids andconducting the resulting' mixture of ammonia salt and concentrated acid.into said open vessels, substantially as and for the purpose stated.

In testimony whereof I have hereunto set my hand in presence of twosubscribing witnesses.

RUDOLPH BRUNCK. Vitnesses:

WILLIAM EssENwEIN, PETER LIEBER.

